Seroprevalence, risk factors and hematological parameters associated with equine infectious anemia from Casanare,...

Equine infectious anemia (EIA) is a persistent lentiviral disease with important sanitary and economic implications in tropical regions; however, epidemiological information in Colombia remains limited.

To estimate seroprevalence, identify risk factors, and evaluate hematological alterations associated with EIA in horses from Casanare, Colombia.

A cross-sectional study including 1,228 horses from 204 production units across 121 rural districts. Serological diagnosis was performed using agar gel immunodiffusion. Demographic and management data were obtained through an epidemiological survey, and hematological parameters were measured using an automated analyzer. Seroprevalence was estimated with 95% confidence intervals (CI). Risk factors were evaluated using Chi-square (χ²) tests and odds ratios (OR), variables with p ≤ 0.50 were included in a backward likelihood ratio (LR) multivariable logistic regression model, and adjusted ORs were estimated for the final model. The hematological parameters were compared using Student's t-test (P < 0.05).

Overall seroprevalence was 8.96% (110/1,228; 95% CI: 7.49-10.69) and 34.1% rural districts reported at least one case. Age >24 months (OR 3.11; 95% CI:1.60-6.043), and geldings (OR 2.37; 95% CI: 1.33-4.20) increased risk, whereas Quarter Horse breed (OR 0.63; 95% CI: 0.15-0.85) were protective. Seropositive horses showed mild hematological alterations involving leukocyte and erythrocyte parameters, consistent with subclinical infection.

With lifelong carrier status and cyclical viremia characteristic of EIA infection, these results highlight the continued dependence on systematic serological surveillance for disease control in endemic regions and provide updated epidemiological evidence to support targeted control strategies in the studied population.